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June 7, 1927.

A. N. CALKINS TRACTOR Original Filed March 25, 1925 2 Sheets-Sheet 1 Gig@ WIIIEr//Hlnfkle June 7, 1927. 1,631,243

A. N. cALKlNs TRACTOR Original Filed March 25. 1925 2 Sheets-Shea?, 2 V" myd Z0 Z1 5l jyb Patented June 7, 1927. *i

PATENT OFF-ICE.

Y ADDISON N. (IALKINS,` F QUINCY, ILLINOIS,V ASSIGNOR TO ELECTRIC WHEEL (101M-V PANY, 0F QUINCYfILLINOIS,

A CORPORATION l OF ILLINOIS.

".rnncfron.

Application led -Harch 25, 1925,` Serial No. 18,089. VRenewed April 1, 1926.

The invention pertains to tractors having an endless chain consisting of a series of separate link sections pivotally connected together so as to travel around spaced rotary supporting members and coacting to restrain flexing in an upward direction as the chain travelsover the ground but permitting a bending or flexing of the chain around the supporting members.

stated is to produce a chain for a tractor of the character referred to, in which the link sections are operatively connected together in a novel and advantageous manner to produce between adjacent links a truss action preventing flexing of the chain upwardly as it passes over the ground, but permitting relative pivotal movement between the sec-l tions for passage around the supporting members.`

In attaining the object thus set forth I provide separate sections adapted to beloperatively connected by links or bars in a manner such that a truss is formed between each pair of adjacent sections.Y The horizontal or tie portion is formed by two adjacent tread portions and the inclined side portions are formed by an. inclined arm on one section and thef connecting bar'between 30 the two sections, the apex of the truss being disposed directly above the joint between the two .tread portions. Theiaim is to simplify the construction of the chain while imparting strength and durability thereto.

In the accompanying drawingsFigure 1. is a fragmentary side elevation section 0fatractor illustrating my invention in. its pre# ferred form. i

Fig. 2 isa fragmentaryhorizontal section takenmpproximatelyin the plane of line 2-2 of Fig. 1.;

Fig. 3 is afragmentary plan view showing two link sections connectedtog'ether.

v Fig. 4 is a fragmentary vertical sectional. view taken approximately in the plane'of line 4-4 of-Fig. 3. y

Fig. 5 is a transverse sectional view taken in the planel of line 5"-5 of Fig.y 4. .h

Fig.` 6 is a perspective view of one of link sections.` Y a i.

While the invention is illustrated in its preferred form it is contemplated that various changes in the construction and arrangement-illustratedl and hereinafter described .may bemade by those skilled in the The object of the invention generally are without departing from the spirit and scope of the invention as expressed in the appended claims. a

. The tractor comprises generally a central frame member 10 elongated in form and providing bearings at opposite ends in which are journaled the axles 11 of two pairs of rotary supporting members or wheels 12. The frame member is mounted substantially midway between its ends to turn on a shaft 13 upon which the tractor frame proper' may by supported in the usual way.

The endless belt or chain is composed of a plurality of similar sections, each comprising a tread portion or shoe 14 generally rectangular iny form and of substantial width. Extending inwardly from this shoe is a frame structure preferably formed integral with the shoe and comprising twor pairs of arms 15 and 16 terminating at their inner ends in a pair of laterally spaced'bearings 17 adapted to support a pivot bolt 18 a substantial distance inwardly of the shoeand approximately in the plane of the-rear edge of the shoe. The outer ends of the arms 15 are respectively formed integral with a pair of laterally spaced bearings 19 at the forward ledge of the shoe 14 from which they extend inwardly and rearwardly in substantially parallel relation for connection with the bearings 17. The outer ends of the arms 16 are formed integral with a pair of laterally spaced bearings 2O at the rear edge of the shoe, from which they extend inwardly while converging slightly for connection at their innerends with the bearings 17.

At opposite sides of the shoe are formed track portions 21, the forward ends of which are constructed to provide bearings 22alined with the bearings 19, these track portions being preferably cored out as indicated at 23 (Fig. 6) to lessen the weight of the section. Suitable reinforcing ribs 24 may be provided on the inner face of the shoe 14 kas indicated clearly in Figure 6.

I The arrangement of the parts is such that the laterally spaced bearings 2O at the rear or trailing edge of the sho-e are adapted to enter between the bearings 22 in the forward edge ofthe next adjacent shoe andthe intermediate bearings 19 thereof. A pivot pin 25 passing through the alined bearings 22` and 19 serves to connect the tread por tions of adjacent link sections pivot-ally together. y. To hold the pivot pin 25 in place each et the bearings 22 has formed at its outer end a pair ot lugs 26 disposed on opposite sides of the bearing aperture, which lugs are apertured to receive a retaining pin 27.

In addition to the pivotal connection thus provided between tread portions ot the link sections there is provided a connecting bar 28 havingl one end pivotally mounted on the pivot bolt 18 ot Vone section and its other end pivotally mounted on the pivot pin of the next or rearwardly adjacent section. rfhus the bar is, like the arms l5, angularly disposed with respect to the tread portions ot the link sections, and occupies normally an approximately perpendicular relation to the arms l5. The outer end ot the'bar is entered between the spaced bearings i9 at the forward edge of one section and its inner end is entered between the bearings 17 of the trame structure of the 'forwardly adjacent section. it said inner endy the member 28 has an elongated head 29 with a slot 30 therein ior receiving the pivot bolt 1S.

lt will be seen that the arms l5 and the bar 28 olt the two adjacent link sections term the inclined sides oi a truss ot which the horizontal connecting portion is formed by the two treadportions of said sections. The construction possesses great strength', etl'ectually resisting upwardly directed torces as the chain passes over the ground, producing in effect a rigid tread et substantial length.l Gn the other hand it permits the link sections to llex readily in the opposite direction tor passage around rotary supporting members, the moven'ient of the inner ends ot the connecting bars 28 relative to the pivot bolt 18. in this operation, presenting no ditticulties from the standpoint of interference between adjacent link sections.

To guide the link sections around the rotary supporting` members l2 the track portions 21 of each section are provided with inwardly extending tlanges 3l at the inner edges ot the track portions; and to cause the link sections to adhere snugly to the peripheries ot the supporting members as they pass around them, means is provided operating to maintain the chain under tension. Thus the axle ll t'or one pair oil supporting members 12 is mounted .in a movable bearing 32 slidable in a bearing box 3B (Fig. l) at one end ot' the iframe member l0. The latter has an opening 3dr therein at one end ot which is mounted a screw 35 having an adjusting nut 3G thereon between which and the bearing 32 is interposedva coiled spring 37, the latter passing through a suitable opening in one side et the bearing box. This construction, while operating to maintain the chain taut serves to reduce noise produced by the links passing around the supporting` members and also prevents injury to the parts by permitting` one of the bearing members to yield relative to the other in the event that a stone or other substance should find its way between the supporting members and the chain.

I claim as my invention:

l. A tractor of the character described having an endless chain composed of a series ot link sections each including a tread portion, means pivotally connecting adjacent tread portions together, an inwardly extending trame structure rigid with each tread portion and having a pivot bearing mounted therein substantially in the vertical plane containing one edge of the tread portion, and a member connecting said pivot bearing and the corresponding edge ot the adjacent tread portion adapted to permit relative pivotalmovement between the sections in one direction and to prevent relative pivotal movement in the opposite direction.

2. A tractor ot the character described con'iprising an endless chain having a series o'lE link sections each including a tread portion, means pivotally connecting adjacent tread portions together` anl inwardly extending trame structure rigid with each tread portion and having a pivot bearing mounted therein substantially in the vertical plane containing one edge ol the tread portion, and a member connecting said pivot bearing and the correspondingr edge of the adj a'cent tread portion adapted to permit relative pivotal movement between the sections in one direction and to prevent relative pivotal movement in the opposite direction, said trame structure including a rigid arm arranged approximately perpendicular to said member.

3. A tractor ot the character described comprising an` endless chain having a series ot link sections each including a tread portion, means pivotally connecting adjacent tread portions together, an inwardly extending rame structure rigid with each tread portion yand having a pivot bearing mounted therein substantially in the vertical plane containing one'edge of thetreadportion, a member connecting said pivot bearing and the corresponding edge ot the adjacent tread portion adapted to permit relative pivotal movement between t-heV sect-ions in one direction and to prevent relative pivotal movement in the opposite direction, said trame structure including a rigid arm arranged approximately vp'erpendicular to said member, 'and a second arm between the inner end of the first arm and the treadrportion.

4. A tractor comprising an "endlesschain composed ot 'a series of link sections each comprising a tread portion and each having an inwardly extending trame structure comprising a pairof armsprojecting approximately perpei'idicularly from one edge of the tread portion, a pair ot inclined 'arms projecting from the oppositel edge of said section, said two pairs of arms terminating to provide a bearing spaced inwardly from one edge of the tread portion, a pivot pin carried by said bearing, pivots connecting the tread portions of adjacent sections. and an inclined member connecting sa'id pivot pin with the remote edge of the tread portion of the adjacent sect-ion, so as to permit relative movement between the adjacent sections in one direction only.

5. A tractor of the character described having an endless chain composed ot' a series of link sections each comprising af tread portion, interlitting bearings at adjacent edges of the. tread portions oit adjoining sections1 pivots mounted in said interlitting` bearings and serving pivotally to connect adjacent tread portions together, a plurality of armsy projecting inwardly from said tread por tions. a pivot supported by said arms in in- Wardly spaced relation to one edge of each tread portion, and a connecting member having an elongated opening in one end adapted to receive the pivot on said arms, the other end of said member being mounted on the pivot connecting the tread portions or" the next tivo adjoining sections. v

(i. In a tractor of the character described, an endless chain composed of a series of link sections each comprising a tread portion, means pivotally connecting said tread p0rtions vtogether in edge to edge relation, and means additionally connecting each two adjacent link sections comprising a pa'ir 0.1"; members normally disposed substantially perpendicnlarly relative to each other, one of said members being rigid with one ot said pair of tread portions and the other one of said members being pivoted to the other tread portion and having a pivotal and sliding connection ivith said rigid member.

7. In a tractor of the character described an endless chain composed of a series of link sections each rcomprising a tread portion` means pivotally connecting said tread portions together in edge to edge relation, and means additionally connecting each tivo adjacent linliy sections comprising a pair of members normally disposed substantially perpendicularly relative to each other, one of said members being rigid with one of said pair oit tread portions and the other one of said members being pivoted to the other tread portion and having a pivotal and sliding connection with said rigid member, each section also including an upright member between the inner end of the rigid .member and the tread portion.

In testimony whereof, I have hereunto at .fixed my signature.

ADDISON N. CALKINS. 

